Commentary: The evolutionary biology of the paternal age effect on telomere length.

Telomeres are repeating sequences of DNA found at the ends of chromosomes, that shorten in most proliferating tissues as we age and our cells replicate. Shortened telomeres result in a reduced capacity for cell proliferation, and in adults have been shown to predict increased morbidity and earlier mortality. Whereas telomeres tend to shorten with cell replications in most tissues, sperm telomere length appears to run counter to this trend by increasing with each cell division, leading to a lengthening of sperm telomeres as men age. As a result, offspring of older fathers have longer telomere lengths. This finding suggests that the age at which a man conceives his offspring might have important influences on his children’s health and longevity by altering the length of telomeres that they inherit. Abraham Aviv and Ezra Susser are leaders in considering this paternal age at conception (PAC) effect on offspring telomere lengths, and their article in this issue is an important review of this topic. In addition to discussing the basic molecular biology and health implications of the PAC effect, they also briefly consider some of the evolutionary dynamics that are implied by this unusual phenomenon. Here we elaborate on the evolutionary significance of the PAC effect and note some points where our interpretations of the literature differ slightly from those of Aviv and Susser.